Sawing Speed Experiment

[YellowHammer]

I don't know how many, if any watch my videos, but I thought some of you might like this one.  It was an experimental progression of several cuts through a 15 inch cant, sawing very slow to wavy fast, and looking at cut quality and sawdust ejection after each cut.  The only thing I changed was sawing speed, which I regulated via my Accuset speed governor, and the results were more than very dramatic.  I thought it might answer some questions that always seem to pop up about washboard, band resonance, sawdust packing, spillage, etc.  It's pretty long because I did several cuts and examined the boards after each and discussed the results in detail.

   

[customsawyer]

I'll have to watch it later but I appreciate you taking the time to make it.

[Ron Wenrich]

I'm a circle mill guy and I also found that there was a certain tone that you needed to have your optimum speed.  The feed rate would vary from log to log, because the width of the board, species, wood temperature, moisture content, etc would vary.  When you're bogging down your engine, you're cutting too fast.

Circle mills also have a problem with gullets filling up.  It comes about from having poor gullets, or feeding to fast.  Feeding too slow isn't much of a problem unless you have poor shanks.  But, circle mills have a dust discharge at the bottom of the cut.  I often wonder what difference it would make if band mills worked like that.  Gravity is your friend. 

Good presentation.

[doc henderson]

Cool video.  I wish my mill would go that fast.

[Machinebuilder]

I watch most of your videos, Thank You for doing them, I have probably learned more from your videos than the other youtubers all together.

I have learned to push my mill until the engine bogs too far.
I found when I switched from the 4degree blades to the 7degree it seems to help with less sawdust left behind.
the saw dust is also coarser.

I had the opportunity to use a friends LT40WIDE with the 26.5hp engine. I found i could saw MUCH faster.
I sawed my first pine on that mill, compared to the red oak I have sawn it is so much easier except for the resin build up.

this video was very interesting to me, coming from a production metalcutting background there is a lot of emphasis on how much material each tooth is removing.
the variables are spindle speed, feedrate, tool geometry, and material. I see the same principles as you are talking about.

[Larry]

The faster the feed rate the slower the blade speed. Blade speed is the secret and there is an optimum range which YH found to be an "E" flat. I agree.

More than 16 years ago pineywoods found another way to find the optimum blade speed. He hooked up a cheap bicycle speedometer to the band wheel. I tried it and what I found is if the blade speed was to fast I got excessive sawdust and rough cuts, same as YH. Blade speed too slow and I got waves. Horsepower is a big help in maintaining the optimum blade speed in those wide cuts. When I hit the optimum speed I started to notice the blade singing. After a while I didn't need the speedometer as I had calibrated my ears.

Remember blade speed is dependent on feed rate, band sharpness, species, and width of cut.

Thanks for the video YH, you probably spent half a day making it to help out other folks.

[taylorsmissbeehaven]

Thank you sir for another great video. Im sure it was painful for you to spend so much time on one log! Very nice to see all of those variables in one spot. I would be interested to know how blade cleaner/lubricants affect those variable. I also wonder if a dust collectioin system has any bearing on amount of sawdust moved off of the log. Thanks again!

[Resonator]

Interesting to see the different sawing speed results.  

You could probably go through the video with sound editing, and isolate the blade sound to find what note it's "singing". Could also try clipping a instrument tuner to the mill itself, but I think the droning of the engine would overwhelm the sound.

[John S]

Will watch later, I always think that I should be going faster,  Currently working on removing the roll in on the debarker in and out motor pulley.

[YellowHammer]

The LT70 has a blade speed display, I should have had a camera on that, as I was sawing.  It should have occurred to me.  Thanks, I'll get it on video. 

I have no musical talent but I should be able to do as Resonator describes and isolate the waveform into any handy spectrum analyzer and see what the primary and secondary frequencies are, I was hoping a few pitch perfect folks would just tell me.  When the band is running right, I swear I can hear harmonics, best described as a "ringing" I guess.  However, with my ears, it may be just the sound of the neighbor's cat in heat.

I wore my starter out on this log, turning the mill off, even turning the dust collector off sometimes so I could talk, then turning everything back on.  It took forever to get this log done and ruined a few boards the process. 

I think I may do one on band cleaners and even one on different band profiles. 

[Hilltop366]

Well I don't have perfect pitch in a sense that I can name the note it is playing out of my head but I keep a guitar next to the sofa and tried it again to compare it and it is still real close to e flat. 

I wonder what effect a different pitch blade would have, would it give you a different note or would you have to adjust your feed rate and end up with the same note?

On the prefect pitch thing I was at a local orchestra concert sitting half way back in a church a few years ago that my sister was playing violin in and after the concert I asked her if the lady playing violin in front of her was a little bit flat....she said I was correct so I guess my ear ain't too bad. 

[doc henderson]

I think a lot of factors may change the pitch but comes down to the vibration frequency. 

I think A# blade would cut the best.     bu-dut-cheee!

[beenthere]

Doc, that is real close to B flat 

But sharp is preferred.

[barbender]

One of the handy things that has come along for guitar tuners are models like a "Snark", which are a small tuner that clips onto the headstock of your guitar. It has a transducer, I think, that picks up the vibrations in the instrument. They're nice because you don't have to plug them in, or have a microphone "hear" the instrument.

I bet one of those would read the tune the band is playing if one attacked it to the mill head somehow.

[beenthere]

A phone app will give the note, I believe.

[Resonator]

One of the handy things that has come along for guitar tuners are models like a "Snark", which are a small tuner that clips onto the headstock of your guitar. It has a transducer, I think, that picks up the vibrations in the instrument. They're nice because you don't have to plug them in, or have a microphone "hear" the instrument.
 

This is what Barbender is referring too. I tried to tune mine down from E to E flat, all I got is D sharp.  
Like I said, I think the engine noise would interfere, but you could try it.

[barbender]

As a side "note", I hate the convention of using letters for notes. Trying to read Eb on sheet music must be torture. 

Some of you guys are "for real" musicians (I'm not) but are you familiar with the Nashville Number System?

[Resonator]

I just hack out 3 chords on the guitar and hope for the best.

Yes, I've heard concept. Nashville recording studios streamlined the music system so a country song could be broken down into 1 to 7 chord parts based on their scale position. Session musicians can quickly learn and play a new song just knowing the part numbers, and putting them in what order the song is written. That way they can record an album quickly, as it's many thousands of dollars an hour to book a studio.

[doc henderson]

some are audible like we used in band for all the instruments.

[Hilltop366]

Not a "real" musician here, mostly strumming chords and a bit of finger picking. I don't use the NNS but somewhat understand it.
My oldest brother who does not read music can transpose a song to another key in his head and it took me a while to figure out how he was doing that. Some cord progressions he just knows in several keys and muscle memory takes over others he thinks of the chords as barre chords and moves the pattern to another key to figure out the cords in the new key. It seems to take about 15 seconds to do.

[Larry]

I think I may do one on band cleaners and even one on different band profiles. 

Band profiles, 7 vs T7......something I've noticed but don't have a good handle on the cause. The standard 7 degree leaves more sawdust on the board and I believe the cause is the smaller gullet. The T7 cleans the board better and cuts faster but I can't get the extra smooth cut of the standard 7. Not really a problem for me but just curious.

[barbender]

You guys are picking up what I'm laying down😊

[Ron Wenrich]

The Nashville system uses numbers instead of letters.  But, when you get to the music theory side, you will get into flatted numbers.  For example, a major chord is 1-3-5, but a minor cord has a flatted 3.

Certain notes will always come up in a progression of a chord.  Certain chords will fall into a key.  The key of G will always have chords of G-Am-Bm-C-D-E-Fm-G.  The key of A would bump them up to the next level.  Or, you can just put a capo on the guitar and that bumps it up for you and you still play the same progression without transposing.

I play pedal steel guitar.  I can use the same progression for nearly any song.  But, when the key changes, I have to change everything with my hand, as my bar is my capo.

For the non-musically inclined, I'm sure that's as clear as mud. 

[doc henderson]

I "play" dobro.  after finding the base cord or the key the song is in, the other cords are 5 and 7 frets up.  If the song had a "bridge" it is 2 frets up.  a bridge is an interesting progression that for the moment sounds like a key change.  sometimes I climb up a fret at a time, or decline using triplets as a classic dobro sound.  I like that for blues.  I would play any sound from you tube and never really know or care what actual key it is in, or care.  If I play with a group, they can name the key, and that is my base cord.  again, with a stevens slide across the fret resting on the strings, (not pressed to the fret).

[doc henderson]

Folsom Prison Blues

Now this is an example in the key of G (so open strum of the dobro is a G cord).  No, this is not me playing.  I am occasionally asked if I am a good dobro player, and I have also been told there is no such thing as a good dobro player.

to stick to the thread, it sounds a little like yellowhammers saw.

[jpassardi]

" However, with my ears, it may be just the sound of the neighbor's cat in heat." 
Appreciate your time investment Robert. 
Forum members may want to subscribe to YH's channel so you get notifications when new videos come out.

My personal experience: upgrading from 15 to 25 HP allowed me to saw considerably faster and make grit rather than powder in wide hard cuts. I have an LCD display on my homemade power feed that lets me dial in and maintain max feed speed for a given hardness/width of cut/blade sharpness. I tune by sound and quick look at the cut then maintain via the display.
The toughest species I've found to cut flat is EWP with large knots - it won't let you ignore a dulling blade and slowing feed will only buy you so many more passes.

[YellowHammer]

I appreciate the thanks, I'm not sure what the future holds for me making videos, it's frustrating dealing with the cameras and stopping to do all the shots, but it's fun coming up with new ideas to film, and documenting or explaining what I'm seeing, and the feedback from the people who watch.

You guys know we sell to some pretty high end country stars and luthiers for their new guitars, and we've had people come in with tuning forks, thump a board, and see which fork vibrates.  I think of them as the wannabes.

The real builders are like the guys who build for the Grand Ol Opry, I watched the anniversary edition show the other night, knowing the presentation guitars were made for our wood.

The Opry guys came in last week, and they are as country as they can be, great guys, but dang they have ears and stories of the stars.  One of the guys was loading some maple onto the trailer, and generally, they thump a board on the concrete floor to hear its tone.  If it sounds "pure" or "clean" they accept it, if not, it goes back on the stack.  "Can't make a sweet guitar from a piece of wood that sounds sour as s**t" as they tell me.  Anyways, I was talking to the owner about the next load of wood they wanted, we were three bays away, other side of the building, and he heard a board he didn't like, and he shouted over to them, "Not that one, it's flat."  Yeah they are that good.

They also build electrics for some of the rockers, and they laugh because they say they have to build them light because "Have you seen that bag o bones?? He's as scrawny as a stick, he ain't got a muscle in his body!"

[TreefarmerNN]

Maybe that's the problem with my sawing- I have a tin ear.

More seriously, that was a great video.  When I started using the mill my thought was slower was a better cut which obviously was wrong, at least up to a point.  Your video really showed in detail the progression from too slow to to fast ending up at the Goldilocks speed.

I've also heard that note when my saw is running just right.  I wonder if the pitch changes with different widths and especially thicknesses of the blade.

[SawyerTed]

Great video!  Cattlepliers?    

Two things will help a person develop an ear for the note and rhythm of machines.  

Farming, especially mowing and baling, will help develop a sense of note and rhythm of machinery.  

Teaching high schoolers in a shop will help a person develop a sense of note and rhythm of machines.  When things "aren't right" there's a chance something dangerous is happening.   Time to intervene.  

Same with a sawmill as Robert so aptly demonstrates in the video.  

[TreefarmerNN]

I absolutely agree about sound and farm machinery.  More than once, I've stopped a machine because the sound changed.  That's one reason I don't want music playing or other distraction while I'm running machinery- I want to hear the machine.  I do use ear plugs on an open station tractor but those don't block the machine sound; they just drop the volume enough so my ears aren't being damaged.

The sawmill is the same way.  I didn't know what note it is playing but there is a "just right" sound.

[JD Guy]

Great video!  Cattlepliers?   

Two things will help a person develop an ear for the note and rhythm of machines. 

Farming, especially mowing and baling, will help develop a sense of note and rhythm of machinery. 

Teaching high schoolers in a shop will help a person develop a sense of note and rhythm of machines.  When things "aren't right" there's a chance something dangerous is happening.  Time to intervene. 

Same with a sawmill as Robert so aptly demonstrates in the video. 

Roger that on "mowing and baling" ! When something's not quite right you recognize it in an instant and stop everything! Better to stop than have to quit and tear down and fix equipment 

[hardtailjohn]

It's ANY machine....they all have a particular sound when you find that sweet spot!! I ran a rock crusher for a couple years, and even it had that sound, and the rhythm of the jaw was the same as the old country song, "Johnny Yuma". 
Yellowhammer, I watch your videos, and I'm a circle saw guy.... but I can't say that there's a one that I haven't learned something from!!! Thank you for the content, for sharing your knowledge, and the humor! I know it's a pain to do, and takes FOREVER to get something done!  I do and teach, airplane fabric covering and try to do videos to try to give some of my students more reference material, and it's a total PIA, but worth it in the long run!!
John

[Ben Cut-wright]

Thank you for that video and all the others. This one was very interesting because "forward blade travel" speed is as much art as science, IMO.  Please pardon my many questions but they do illustrate my interest in your video.  Not asking for expansive; all encompassing, definitive replies to my questions, only your opinion and experiences. 

At 35:03 when it appeared the first wave began...the forward travel was slowed down greatly:

(1) Was this because the head travel motor was overloaded (or belt slipping) because the blade wasn't opening the cut fast enough? 

(2) Was the excessive engine load at the same instance as the forward travel slowdown, or were you aware of the engine becoming loaded *prior to the wave and slowdown? 

(3) In other words, did you back-off forward travel, let the engine recover, and then return to the *same forward speed that caused the bog?

(4) The note *change in the blade was difficult for me to determine at the forward travel rate which produced waves.  Were you able to determine the change in tone when the *excessive forward rate was used. 

(5) Were you aware of how far the blade is pushed back on the rollers when the proper note is achieved? 

It is known, and your video demonstrated, that the blade cutting 'note' is a good indicator of proper forward travel speed. 

(1) Can that note be heard when the blade is dull, not lubricated properly, or not tensioned properly?

(2) Will every profile and width band blade have the same/similar note when cutting properly.

Lastly, knowing to be aware of the proper blade note is valuable.  Knowing what *creates the note and how to achieve the proper sound might be just as important.

(1)  Is the blade expected to create the proper note in all widths of cut?

(2) Will most species of wood affect the blade note in similar fashion?

(3) You stated that in another video you were gonna experiment with blade lubes/coolants.  Knowing you prefer diesel, do you anticipate blade note tone to be altered with other lubes or amounts of lube? 

[barbender]

hardtailjohn, a rock crusher is exactly what this conversation made me think of. Whenever the sound of something on the set changed, you wanted to be running for the master shut down- especially if you were the oiler and got to shovel up all of whatever backed up from a conveyor, screen, or cone crusher. I will say I was probably in the best shape of my life when I was oiling on a crusher!

[Magicman]

Thank You Robert for a most excellent tutorial video and for taking the time to make it.

You verified my normal of sawing "against the engine".  The instant I hear/feel the engine RPM drop, I instantly reduce my sawing speed. 

[240b]

well, this is timely.  last week i started sawing again after winter logging was done.  I had wood "flour"on the sawn lumber.  Nothing had changed for last fall,  except i am now sawing partially frozen logs. 
after emails to blade manufacturer 
i've reduced the set, reduced the engine rpms and increased the feed rate.  the sound of the blade is almost louder than the engine now.  
 Never experienced any waviness just wood "paste" frozen to the lumber.  
  
  

[TroyC]

Very nice! Thank You!

[YellowHammer]

Thanks all.
Ben,
Yes, even though I had it in forward speed governed, I had my hand on the joystick and as soon as I heard the board scrubbing on the band, I pulled back on the joystick, and let the engine recover.  It should be noted that the decrease in engine RPM is not just from too much cutting tooth load, but as the band waves, the band tension and friction of the body of the band against the side of the saw kerf will put a tremendous load on the band as it presses agains the wood from friction.  Recoveries of a wave must be extremely quick or the engines loads almost exponentially, and bad things happen, including desetting the teeth in some instances.  So after a bad wave, it's sometimes likely the band is overheated or un-set and is otherwise done.

I could "hear the wave" of the band rubbing on the kerf before I heard the engine start to slow down.  Again, it's a sound thing.  Very distinct and very fast.  It's the first warning of the band friction increasing and by the time the wave started I had already pulled back on the joystick.  The second wave was because I figured the camera would miss it, so as soon as I felt things settle, I jammed the joystick against the governor and did it again.  After that, I felt that that the band wasn't recovering to neutral fast enough, so I really slowed down to exit the cut to let things settle down.  At the point, I was just hoping I had not ruined my band.  That's also why ion the video I said "We should see a wave" even though I had not actually seen it, I knew they were there.

That's also later, why when I was sawing the narrower cant, I was going slower than optimum, I wanted to see how the band was behaving before I opened it up again, and ruined more boards.  The band was probably back to 90% cutting behavior, so I was able to finish up, but did take it off after that log.

Yes, I can hear a dull band, certainly not lubricated properly, but tension is a secondary thing as the band will wave prematurely, and I always have my pressure gauge rotated to the 12 O'clock position so even far away, I can quickly tell if my band tension has dropped.  That is imperative.

I have never had a band by any manufacturer or tooth angle that did not make the ringing sound when it was cutting well.  That being said, it's one of the ways I judge a band geometry, by seeing how wide a margin of forgiveness it gives me.  As a matter of fact, a couple years ago at Jakes sawing project, while he was slicing up the 43 foot cypress, I had a few guys next to me ask about the ringing I mentioned on some of my previous videos and I said, just wait, Jake will hit it and you can hear it.  Sure enough, Jake nailed it, and I said "hear it?" and a whole bunch of guys exclaimed "Yeah! I get it now."  Actually there was a line of people coming up to listen and since it was a decent sized log, it took a bunch of cuts and pretty much everybody had time to hear it.  I wish I had filmed that one.  Of course, I knew Jake wouldn't disappoint, he love to saw fast, too.

As far as widths of cut, yes, that's why I went with a decent sized 15" cant, I knew I had the horsepower to let it sing.   

I am going to do one on lubricants, and although I think diesel is the best band cleaner, for 9 months out of the year, I generally use cotton picker spindle oil.  I only use diesel in the coldest months as it will not freeze and the CPSO will turn into a slushy milkshake.  Both are used with a very low setting so stank will last along time. 

Yes, if a blade lube is not working, the tone will be affected because the sap is building up, kind of like putting chewing gum on a guitar string, it won't sound close to right.  I will not use any lubricant that does not give me a shiny, slick band.  Very, very few will do that with consistency.   

[Dave Shepard]

I watched a few of my sawing videos, and I could hear the ringing. I walk with my mill, and I don't notice it as well as I do when watching the videos. 

[Peter Drouin]

What it comes down to, Is you have to cut enough lumber to be one with your sawmill.   

[WV Sawmiller]

Great video. Thanks.

[Magicman]

I had to relearn my sawing speed & rhythm when I finally had to go with my non-turbo engine vs the old turbo.  The non-turbo simply does not have the torque to push the blade as I was accustomed to doing.  Each individual's sawing speed is a fine line between their engine and their chosen blade profile and of course the log species enters into the equation.

[Ben Cut-wright]

Ben,

 So after a bad wave, it's sometimes likely the band is overheated or un-set and is otherwise done.

I could "hear the wave" of the band rubbing on the kerf before I heard the engine start to slow down.  Again, it's a sound thing.  Very distinct and very fast.  It's the first warning of the band friction increasing and by the time the wave started I had already pulled back on the joystick. 

Yes, I can hear a dull band, certainly not lubricated properly, but tension is a secondary thing as the band will wave prematurely, and I always have my pressure gauge rotated to the 12 O'clock position so even far away, I can quickly tell if my band tension has dropped.  That is imperative.

I have never had a band by any manufacturer or tooth angle that did not make the ringing sound when it was cutting well. 
As far as widths of cut, yes, that's why I went with a decent sized 15" cant, I knew I had the horsepower to let it sing.   

Yes, if a blade lube is not working, the tone will be affected because the sap is building up

Again, many thanks for clarification and answers.  Very helpful.

Removing a band blade after it's made severe wave/waves in a cut is SOP for me.

The timing between when you sensed the change in tone beginning and you slowing the forward speed was the major factor in forward travel slowdown then?  Not particularly the forward travel motor stalling?  Most likely there isn't time to slow the forward travel sufficiently to prevent a wave even if the change in tone is noted. So...trick is to increase cutting speed until the tone is heard and then maintain/adjust speed to retain the tone.

Blade tension:  Would expect tension to increase in a *wave, then perhaps decrease after the wave, or perhaps drop *significantly (below specs) at the end of a cut.  Your blade apparently recovered tension after the wave as the tone returned in the cut after both waves.  Also set must NOT have been affected. Like you said, it is quite likely that a severe wave will alter set, and the second wave changing directions might indicate it was *likely, but didn't happen in your case.

"HP to let it sing": Very poetic words.  You have a knack for conveying thought.  So..HP...is a factor.  You say "band by any manufacturer or tooth angle that did not make the ringing sound when it was cutting well".  The LT70 HP wasn't enough to prevent the blade from losing tone and making waves.  Slowing forward travel would have maintained proper cutting tone... as the cut prior to the wavy cut proved.  Is proper cutting tone to be expected/striven-for no matter the HP? 

A shiny clean band is one of the primary requirements, imo.  If the band body doesn't freely *move in the cut your bubble gum analogy is quite pertinent. So NO matter what restricts the band body in the cut, its ability to sing is restricted.  And proper cutting tooth *loading must be achieved to set up the vibrations in order for the band to create the tone. 

Tensioning the band might be compared to the "turning pegs" of a guitar.  The rollers might be compared to the frets. Strumming the band (the teeth properly loaded in the cut) creates the desired "note". 

[Rhodemont]

I did a trial on a 13 inch wide Ash cant yesterday as Robert did in his video. I ran a new Woodmizer double hard 4 Degree band and gave the mill a once over for settings and tensions before starting.  I use the Magic Man glub glub of dish detergent as a lube with a squirt of diesel after each pass.  My LT35 with 25 hp gas can not go anywhere near the speed of a LT70 but as Robert points out each mill will have it's own sweet spot.  Also, with my speed controlled by potentiometer it is not as precise as the digital control.
-Speed 1  was a creep and left lots of saw dust and tooth marks
-Speed 2 reduced both.
-Speed 3 (which is about Roberts speed two) got better.
-Speed 4 was the best with least sawdust and no teeth marks.  The motor was working and band producing a note.
-Speed 5 stopped the mill, not the engine but the new travel drive belt started to slip.  (it was tensioned plenty tight).

Speed 4 was with the potentiometer at about 1/3 of the dial.  This is about where I run typically.  Speed 5 was at about 1/2 dial where I almost never run except narrow stuff.  I did not reach the same note that Robert can make but feel confident that I can hear and feel when I am running at optimum , and it is different in ash vs oak vs poplar etc. 

[Magicman]

I generally saw with the potentiometer at about 2:00, but then again, I am tuned in for my engine, T 7 blades, and log species.  A 5 gallon jug of lube will normally last me over a week.

[terrifictimbersllc]

Thanks, Robert that was a very methodical illustrative session there.

As you know, we have the same sawmill except I think yours is tier 3 mine is tier 4. And we use exactly the same blade.  I'm guessing that your band speed does not vary with sawing rate until you overload it like on your last wavy cut. Mine doesn't. Blade speed is set at 5800 in the settings, but for some reason it comes out to about 5550 on the upper right display when the band is revved.Not sure why the difference. Anyway, I would wonder what is your band speed when you get a chance. Mine maintains the same speed When band is running, regardless of feed rate, until going to fast and I hear the engine/band slow and I am in wavy cut territory. I'd like to calibrate mine similarly to yours with the distance of the band marks when I can get a similar cant.

[aigheadish]

I'm training a guy at work right now and I just described a state that our machines get to when everything is ready to go and said you can often here a faint tone change when it's up and running. Printing equipment!

[GAB]

Mr. Milton:
Thank you for the time you spent for our education.
Also, thank you for sacrificing a board or two for the show and tell.
GAB

[kkcomp]

Robert, I can not thank you enough for doing the videos. Your videos are a highlight to my week and much anticipated. Even my wife asks if I saw my weekly video with the sawmill guy and his supervising dog chip. I only mill for myself and started to "save money". However, since finding this forum and your videos I have added the pursuit of perfection. You have made videos based on questions I have asked and that has boosted my desire to do even better. Recently due to an unexpected early retirement and a death in the family I have found milling to be therapeutic and fun as well. Your videos always give me a new level to strive for and have even helped me get a few younger folks interested.